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import time
from umqtt.simple import MQTTClient
from machine import Pin
from dht import DHT22

SERVER = 'X.X.X.X'  # MQTT Server Address (Change to the IP address of your Pi)
CLIENT_ID = 'ESP32_DHT22_Sensor'
TOPIC = b'temp_humidity'
running = True

client = MQTTClient(CLIENT_ID, SERVER)
client.connect()   # Connect to MQTT broker

sensor = DHT22(Pin(15, Pin.IN, Pin.PULL_UP))   # DHT-22 on GPIO 15 (input with internal pull-up resistor)


def run():
    while running:
            try:
                    sensor.measure()   # Poll sensor
                    t = sensor.temperature()
                    h = sensor.humidity()
                    tm = time.localtime(time.time())
                    if isinstance(t, float) and isinstance(h, float) and tm[0] > 2000:  # Confirm sensor results$
                            msg = (b'{0:n},{1:n},{2:n},{3:n},{4:n},{5:3.1f},{6:3.1f}'.format(tm[0], tm[1], tm[2]$
                            client.publish(TOPIC, msg, retain=True)  # Publish sensor data to MQTT topic
                            print(str(msg))
                            print('Sent to ' + SERVER + ' as ' + CLIENT_ID + '. Exiting.')
                            running = False
                    else:
                            print('Invalid sensor readings.')
            except OSError:
                    print('Failed to read sensor.')
            time.sleep(1)

抱歉导入整个脚本。由于它很短，我认为能够看到所有这些可能很有价值。我在脚本顶部导入时间，据我所知，所有变量在使用之前都会被引用。

我想将此脚本作为 dht_publish 导入，然后运行 ​​dht_publish.run()。但是，这会产生以下错误。这是在 ESP32 开发板上的最新 MicroPython 二进制文件上运行的。

 Traceback (most recent call last):
  File <stdin>, line 1, in <module>
  File dht_publish.py, line 33, in run
 NameError: local variable referenced before assignment

如果我注释掉 time.sleep(1) 行，则错误会在之前的行上标记，这表明错误可能在代码中的其他地方，但我看不到在哪里。对此的任何帮助将不胜感激。

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1 回答 1

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如果有人在尝试类似的事情并遇到同样的问题，问题是函数中的running变量run正在查找局部变量。解决问题后将变量的定义running移至第一行。def run():

于 2018-08-25T21:08:06.417 回答